Microscopes are employed in a wide variety of fields to view various types of biological and non-biological samples. Most microscopes are limited to generating two-dimensional (2D) images of a sample. However, obtaining three-dimensional (3D) views of a sample would be desirable in order to provide better information as to feature shape, topography, and spatial distribution. Currently, 3D images may be acquired by scanning the axial depth of focus through the sample. The focal stack of images acquired in this manner may then be post-processed using 3D deconvolution algorithms and blending techniques to generate 3D views of the sample. However, the computation required makes these techniques slow and non-real time, and discrete axial sampling results in limited 3D information or artifacts in the 3D view.
A light-field camera employs a microlens array in front of its image sensor to capture four-dimensional (4D) light field data from a target object, collecting both the intensity components and directional (or angular) components of light rays emanating from the target object. The light field information may be utilized to generate 3D images of the target object. A common application of light fields in the area of computer graphics deals with rendering objects in three dimensions using intensity and/or direction information. In this case, light fields are often synthesized or simulated under certain realistic assumptions that are intended to place the objects in a three dimensional perspective.
It would be useful to acquire and process light field data in the context of microscopy. The measurement of image intensity and direction information from a biological sample or other sample being studied would enable novel post-processing of the images to look at perspective view, synthetic focusing through the focal stack (without needing to collect additional Z-scan data), and 3D rendering of the sample. For example, presenting the nucleus and features of a biological sample in a 3D perspective would provide additional structural context to the images. The ability to generate perspective views in a regular microscope is especially interesting as it is counterintuitive to the telecentric arrangement of the optical elements in the light path of the microscope, which gives only a 2D projection with negligible depth cues about the sample.